Modeling of emergent memory and voltage spiking in ionic transport through angstr\"om-scale slits

TL;DR

This paper develops an analytical model and simulations to understand ion transport in angstrom-scale slits, revealing memristor effects and voltage spiking phenomena that mimic neural activity in nanofluidic systems.

Contribution

It introduces a new analytical theory supported by molecular dynamics simulations to describe nonlinear ion transport and emergent neuromorphic behaviors in monolayer electrolytes.

Findings

Ions form elongated clusters under electric fields, leading to hysteretic conduction.

Memristor effects enable the creation of elementary neuron models.

Voltage spikes similar to neural activity are observed in nanofluidic slit simulations.

Abstract

Recent advances in nanofluidics have enabled the confinement of water down to a single molecular layer. Such monolayer electrolytes show promise in achieving bio-inspired functionalities through molecular control of ion transport. However, the understanding of ion dynamics in these systems is still scarce. Here, we develop an analytical theory, backed up by molecular dynamics simulations, predicting strongly nonlinear effects in ion transport across quasi-two-dimensional slits. We show that under an electric field, ions assemble into elongated clusters, whose slow dynamics result in hysteretic conduction. This phenomenon, known as memristor effect, can be harnessed to build an elementary neuron. As a proof-of-concept, we carry out molecular simulations of two nanofluidic slits reproducing the Hodgkin-Huxley model, and observe spontaneous emission of voltage spikes characteristic of neuromorphic activity.